This article contains information on why the EventsPublishedContent event does not fire when using a service to add the product.
The content published events are not fired because the service API uses the low level API to update catalog content. It is on the backlog to use the content API. For now, Engineering recommends listening to CatalogEventHandler events and proceeding in that manner.
Commerce R&D made changes in the latest 10.1.1 package to make cross-reference of metafields (for example, using a meta field in both catalog and order contexts) an exception/error, hence why the error upon upgrade.
Technically speaking, there's nothing inherent in Commerce that would prevent you to make the cross-reference, but it seems that due to some other bug fix or fixes in 10.1.1 it perhaps necessitated that there be additional checks on the meta data structure (and the erro...